These are the problems I've experienced with my iPhone 4. I can literally pause and resume a loading web page just by touching my finger to "The Spot".
FYI: I did not make this video to dissuade anyone from buying the iPhone 4, but merely to record this phenomenon. If it's a bug, it'll be fixed. If it's a defect, Apple will replace it. I'm very much enjoying iPhone 4.
It's kinda fun, actually.
For what it's worth, I couldn't get it to reproduce in a cafe a few days later, so this could be a problem only in some areas.